The invention relates more particularly to batteries providing high power per unit mass. Such batteries, using the Li-SOCl.sub.2 or the Li-SO.sub.2 Cl.sub.2 couple are capable of delivering powers of several hundred of kilowatts while evolving the equivalent of 10% to 20% of the delivered energy in the form of heat. Unless such a battery is cooled, the lithium may melt, thereby destroying the battery long before the battery is fully discharged.
It is therefore essential to remove the heat evolved by the electrochemical reaction and to evacuate it initially out from the electrochemical block, and eventually out from the enclosure containing the electrochemical block.
The problem is difficult to solve in Li-SOCl.sub.2 or Li-SO.sub.2 Cl.sub.2 batteries in the form of a Volta pile in which each cell is constituted by very thin components having a small inter-electrode distance. For example each cell may comprise:
a porous cathode which is a few tenths of a millimeter thick;
a separator which is about one-tenth of a millimeter thick;
a lithium anode which is about one-tenth of a millimeter thick; and
a nickel-plated copper current collector which is a few hundredths of a millimeter thick.
The copper current collector may be used to conduct heat, but its thickness cannot be increased because of the increase in weight that that would entail.
Further, the electrodes cannot be moved further apart since an increased gap would give rise to a sharp fall in the performance of the battery.
The aim of the present invention is to provide a structure which nevertheless enables the heat generated therein to be evacuated.